The 1999 Oklahoma tornado outbreak was a significant

tornado outbreak __NOTOC__ A tornado outbreak is the occurrence of multiple tornadoes spawned by the same synoptic scale weather system. The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least two rotational ...

that affected much of the Central and parts of the

Eastern United States The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...

, with the highest record-breaking wind speeds of . During this week-long event, 154 tornadoes touched down (including one in

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tota ...

). More than half of them were on May 3 and 4 when activity reached its peak over Oklahoma,

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to ...

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the so ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, and

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the ...

. The most significant tornado first touched down southwest of

Chickasha, Oklahoma Chickasha is a city in and the county seat of Grady County, Oklahoma, United States. The population was 16,036 at the 2010 census. Chickasha is home to the University of Science and Arts of Oklahoma. The city is named for and strongly connect ...

, and became an F5 before dissipating near

Midwest City Midwest City is a city in Oklahoma County, Oklahoma, United States, and a part of the Oklahoma City metropolitan area. As of the 2010 census, the population was 54,371, making it the eighth largest city in the state. The city was developed in ...

. The tornado tore through southern and eastern parts of

Oklahoma City Oklahoma City (), officially the City of Oklahoma City, and often shortened to OKC, is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, it ranks 20th among United States cities in population, an ...

and its

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of Bridge Creek,

Moore Moore may refer to: People * Moore (surname) ** List of people with surname Moore * Moore Crosthwaite (1907–1989), a British diplomat and ambassador * Moore Disney (1765–1846), a senior officer in the British Army * Moore Powell (died c. 1 ...

, Del City,

Tinker Air Force Base Tinker Air Force Base is a major United States Air Force base, with tenant U.S. Navy and other Department of Defense missions, located in Oklahoma County, Oklahoma, surrounded by Del City, Oklahoma City, and Midwest City. The base, origin ...

and

, killing 36 people, destroying more than 8,000 homes, and causing $1.5 billion in damage. With a total of 72 tornadoes, it was the most prolific tornado outbreak in Oklahoma history, although not the deadliest.

Meteorological synopsis

Meteorological setup of the 1999 Oklahoma tornado outbreak

The outbreak was caused by a vigorous upper-level trough that moved into the Central and Southern Plains states on the morning of May 3. That morning, low stratus clouds overspread much of Oklahoma, with clear skies along and west of a

dry line A dry line (also called a dew point line, or Marfa front, after Marfa, Texas) is a line across a continent that separates moist air and dry air. One of the most prominent examples of such a separation occurs in central North America, especially ...

located from Gage to

Childress, Texas Childress ( ) (established 1887; incorporated 1890) is a city in Childress County, Texas, United States. The population was 6,905 at the 2010 census. It is the county seat of Childress County. The city and county were named in honor of George C ...

. Air temperatures at 7:00 a.m. Central Daylight Time ranged in the mid to upper 60s °F (upper 10s to near 20 °C) across the region, while

dew point The dew point is the temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content. When cooled below the dew point, moisture capacity is reduced and airborne water vapor will c ...

values ranged in the low to mid 60s °F (mid to upper 10s °C). The

Storm Prediction Center The Storm Prediction Center (SPC) is a US government agency that is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service (NWS), which in turn is part of the National Ocean ...

(SPC) in

Norman, Oklahoma Norman () is the third-largest city in the U.S. state of Oklahoma, with a population of 128,097 as of 2021. It is the largest city and the county seat of Cleveland County, Oklahoma, Cleveland County, and the second-largest city in the Oklahoma C ...

, a division of the

National Weather Service The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...

, initially issued a slight risk of severe thunderstorms early that morning stretching from the Kansas-Nebraska border to parts of southern Texas, with an intended threat of large hail, damaging winds and tornadoes. Radar May 3, 1999 KTLX (small)

By late morning, the low cloud cover began to dissipate in advance of the dry line, but during the afternoon hours high cirrus clouds overspread the region, resulting in filtered sunshine in some areas that caused atmospheric destabilization. The sunshine and heating, combined with abundant low-level moisture, combined to produce a very unstable air mass. Upper air balloon soundings observed strong directional

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizon ...

, cooling temperatures at high atmospheric levels, and the increased potential of

CAPE A cape is a clothing accessory or a sleeveless outer garment which drapes the wearer's back, arms, and chest, and connects at the neck. History Capes were common in medieval Europe, especially when combined with a hood in the chaperon. T ...

values potentially exceeding 4000 J/kg, levels that are considered favorable for

supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms ...

s and tornadoes. As observations and forecasts began to indicate an increasing likelihood of widespread severe weather conditions even more favorable for strong tornadoes, the SPC issued a moderate risk of severe weather at 11:15 a.m. CDT for portions of Kansas, Oklahoma and Texas along and near the

Interstate 40 Interstate 40 (I-40) is a major east–west Interstate Highway running through the south-central portion of the United States. At a length of , it is the third-longest Interstate Highway in the country, after I-90 and I-80. From west to ea ...

corridor. By 3:00 p.m. CDT, it had become evident that a widespread severe weather event was imminent; the Storm Prediction Center upgraded locations within the moderate risk area to a high risk of severe weather around 4:00 p.m. CDT as wind shear profiles, combined with volatile atmospheric conditions, had made conditions highly conducive for a significant tornadic event across most of Oklahoma, southern Kansas and north Texas, including the likelihood of violent, damaging tornadoes. The SPC issued a tornado watch by mid-afternoon as conditions gathered together for what would be a historic tornado outbreak. By the time thunderstorms began developing in the late-afternoon hours, CAPE values over the region had reached to near 6,000 J/kg. Large

thunderstorms developed, and in the late afternoon through the mid-evening hours of that Monday, tornadoes began to break out across the state.

Confirmed tornadoes

* Note: The above amount refers to the rest of the outbreak, not just the ones confirmed in Oklahoma.

Bridge Creek–Moore, Oklahoma

At approximately 3:30 p.m. CDT, a severe thunderstorm began forming in Tillman County in southwestern Oklahoma; a

severe thunderstorm warning A severe thunderstorm warning (SAME code: SVR) is a severe weather warning product issued by regional offices of weather forecasting agencies throughout the world to alert the public that severe thunderstorms are imminent or occurring. A sev ...

was issued for this storm by the National Weather Service Weather Forecast Office in Norman at 4:15 p.m. CDT. The storm quickly developed supercell characteristics and began exhibiting potentially tornadic rotation, resulting in the National Weather Service issuing the first

tornado warning A tornado warning (SAME code: TOR) is a severe weather warning product issued by regional offices of weather forecasting agencies throughout the world to alert the public when a tornado has been reported or indicated by weather radar within the p ...

of the event for Comanche, Caddo and Grady counties approximately 35 minutes later at 4:50 p.m. CDT. The first tornado from this supercell touched down east-northeast of Medicine Park at 4:51 p.m. CDT; it produced four additional tornadoes as it tracked northeast into

Caddo County Caddo County is a county located in the U.S. state of Oklahoma. As of the 2010 census, the population was 29,600. Its county seat is Anadarko. Created in 1901 as part of Oklahoma Territory, the county is named for the Caddo tribe who were ...

, the strongest of which (rated as an F3) touched down west-southwest of Laverty and dissipated west-northwest of downtown Chickasha. This large tornado had exhibited a companion satellite tornado for a few minutes. The storm produced the most significant tornado of the outbreak, which touched down just southwest of the Grady County community of

Amber Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In M ...

at 6:23 p.m. CDT and headed northeast, parallel to Interstate 44, just after another tornado had passed over the airport in Chickasha. The storm continued moving northeast, destroying the community of Bridge Creek and crossing I-44 just north of Newcastle. The tornado then crossed the

Canadian River The Canadian River is the longest tributary of the Arkansas River in the United States. It is about long, starting in Colorado and traveling through New Mexico, the Texas Panhandle, and Oklahoma. The drainage area is about .Bridge Creek, around 6:54 p.m., a Doppler On Wheels mobile Doppler

weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...

detected wind speeds of inside the tornado at an elevation of . These winds, however, occurred above the ground, and winds at the surface may not have been quite this intense. The tornado continued on into Moore, then passed over the intersection of Shields Boulevard and Interstate 35 and back into

, crossing Interstate 240 near Bryant Avenue. The storm then turned more northerly, striking parts of Del City and

near Sooner Road as an F4. The storm damaged and/or destroyed several businesses, homes and churches in Midwest City. Some damage in this area was rated as high-end F4, although F5 was considered. The tornado diminished over Midwest City and finally lifted near the intersection of Reno Avenue and Woodcrest Drive. Thirty-six people died in this tornado, and over 8,000 homes were badly damaged or destroyed. The tornado caused $1 billion in damage, making it the second-costliest tornado in U.S. history, and the most costly in history from 1999 to 2011, at which point it was surpassed by the 2011 Tuscaloosa–Birmingham tornado and again by the 2011 Joplin tornado. It was also the deadliest tornado to hit the U.S. since the April 10, 1979 F4 tornado that hit

Wichita Falls, Texas Wichita Falls ( ) is a city in and the seat of government of Wichita County, Texas, United States. It is the principal city of the Wichita Falls Metropolitan Statistical Area, which encompasses all of Archer, Clay, and Wichita counties. Accordi ...

, which killed 42 people.

Cimarron City–Mulhall–Perry, Oklahoma

Late in the evening on May 3 at 9:25 p.m. CDT, a destructive tornado touched down southwest of Cimarron City in Logan County, Oklahoma, eventually hitting the town of Mulhall, located north of Guthrie. This wedge tornado, which tracked a path, was very wide and at times exceeded one mile (1.6 km) in width. According to

storm chasing Storm chasing is broadly defined as the deliberate pursuit of any severe weather phenomenon, regardless of motive, but most commonly for curiosity, adventure, scientific investigation, or for news or media coverage. A person who chases storm ...

meteorologist Roger Edwards, it may have been as violent or more than the F5 Bridge Creek–Moore tornado (however, it was officially rated as an F4). A Doppler On Wheels (DOW) mobile radar observed this tornado as it crossed Mulhall. The DOW documented the largest-ever-observed core flow circulation with a distance of between peak velocities on either side of the tornado, and a roughly width of peak wind gusts exceeding , making the Mulhall tornado the largest tornado ever measured quantitatively. The DOW measured a complex multi-vortex structure, with several vortices containing winds of up to rotating around the tornado. The 3D structure of the tornado has been analyzed in a 2005 article in the '' Journal of the Atmospheric Sciences'' by Wen-Chau Lee and Joshua Wurman. The tornado severely damaged or destroyed approximately 60–70% of the 130 homes in Mulhall, destroying the Mulhall/Orlando Elementary School and toppling the city's

water tower A water tower is an elevated structure supporting a water tank constructed at a height sufficient to pressurize a distribution system for potable water, and to provide emergency storage for fire protection. Water towers often operate in conjun ...

. After the tornado dissipated at approximately 10:45 p.m. CDT in southeastern Noble County, northeast of

Perry Perry, also known as pear cider, is an alcoholic beverage made from fermented pears, traditionally the perry pear. It has been common for centuries in England England is a country that is part of the United Kingdom. It shares land ...

, many of the same areas of Logan County struck by the Mulhall tornado were hit again by an F3 tornado produced by a separate supercell that touched down south of

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at 11:33 p.m. CDT. Damage caused by this tornado was indistinguishable from damage caused by the earlier F4 tornado. 25 homes were destroyed and 30 others were damaged near Crescent, with much of the damage believed to have been caused by both tornadoes.

Stroud, Oklahoma

At 10:10 p.m. CDT, a damaging tornado touched down north-northeast of

Sparks Sparks may refer to: Places *Sparks, Georgia * Sparks, Kansas *Sparks, Kentucky *Sparks, Maryland * Sparks, Nebraska *Sparks, Nevada *Sparks, Oklahoma *Sparks, Texas * Sparks, Bell County, Texas * Sparks, West Virginia Books * ''Sparks'' (Raffi ...

in Lincoln County, Oklahoma, with only sporadic tree damage occurring as it tracked north-northeast toward

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. Scattered damage of high-end F0 to low-end F1 intensity occurred to some homes and businesses on the southeast side of Davenport, though a house located just south of town lost more than half of its roof. As the tornado continued to track northeast, parallel with Interstate 44 and State Highway 66,

Stroud Stroud is a market town and civil parish in Gloucestershire, England. It is the main town in Stroud District. The town's population was 13,500 in 2021. Below the western escarpment of the Cotswold Hills, at the meeting point of the Five ...

took a direct hit as the storm intensified to F2 strength; the trucking terminal of the Sygma food distribution warehouse on the west side of town was destroyed with some girders and siding from the warehouse thrown northwest across State Highway 66, and the Stroud Municipal Hospital suffered significant roof damage, which resulted in significant water damage within the building. The most severe damage, consistent with an F3 tornado, occurred at the Tanger Outlet Mall at 10:39 p.m. CDT with almost all of the stores suffering roof damage at minimum, though sections of seven storefronts were destroyed and the exterior walls of the Levi's store were collapsed inward. The mall was evacuated in advance of the tornado, resulting in no injuries or loss of life in the building. The tornado finally dissipated south of Stroud Lake at 11:48 p.m. CDT. While there were no fatalities overall in Stroud, the economic impact of the tornado has been compared to the loss of Tinker Air Force Base, General Motors, and a major regional hospital for the Stroud region as compared to Oklahoma City at that time. Approximately 800 jobs were lost in a community of approximately 3,400 people due to the damage of the Sygma distribution warehouse and Tanger Outlet Mall, neither of which were rebuilt. Stroud's recovery was later complicated by the September 11, 2001, terrorist attacks, although the town has since recovered as a result of higher oil and gas prices. Local leading industries include Service King, an oilfield manufacturing facility, and Mint Turbines, a helicopter engine reconditioning facility. Stroud is also now a downloading facility location for oil produced in the northern United States into the Cushing pipeline network.

Other tornadoes

The May 3 tornado event was part of a three-day event that included tornadoes in the states of

and

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to ...

. A deadly F4 tornado that tracked across south-central Kansas killed six people in Haysville and Wichita during the late evening of May 3. Other fatalities during the event included one person killed in Texas on May 4 by an F3 tornado that tracked from near Winfield, Texas, to southwest of Mineral Springs, Arkansas, and three people killed in

on May 5 and 6 by an F4 tornado that struck the town of Linden.

Non-tornadic events

Flash flooding killed one person in

Camden County, Missouri Camden County is a county located in the U.S. state of Missouri. As of the 2020 Census, the population was 42,745. Its county seat is Camdenton. The county was organized on January 29, 1841, as Kinderhook County and renamed Camden County in 1 ...

, on May 4. On May 6, lightning struck and killed a man in

Cobbtown, Georgia Cobbtown is a city in Tattnall County, Georgia, United States. The population was 311 at the 2000 census. History A variant name was "Corsica". The Georgia General Assembly incorporated the place as the "Town of Cobbtown" in 1905. Geography Cob ...

Aftermath

Disaster assistance

On May 3–4, the day after the initial outbreak event,

President President most commonly refers to: *President (corporate title) * President (education), a leader of a college or university *President (government title) President may also refer to: Automobiles * Nissan President, a 1966–2010 Japanese f ...

Bill Clinton William Jefferson Clinton (Birth name, né Blythe III; born August 19, 1946) is an American politician who served as the 42nd president of the United States from 1993 to 2001. He previously served as governor of Arkansas from 1979 to 1981 ...

signed a federal disaster declaration for eleven Oklahoma counties. In a press statement by the

Federal Emergency Management Agency The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Exe ...

(FEMA), then-director James Lee Witt stated that "The President is deeply concerned about the tragic loss of life and destruction caused by these devastating storms." The

American Red Cross The American Red Cross (ARC), also known as the American National Red Cross, is a non-profit humanitarian organization that provides emergency assistance, disaster relief, and disaster preparedness education in the United States. It is the desig ...

opened ten shelters overnight, housing 1,600 people immediately following the disaster, decreasing to 500 people by May 5. On May 5, several emergency response and damage assessment teams from FEMA were deployed to the region. The

United States Department of Defense The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national secur ...

deployed the 249th Engineering Battalion and placed the U.S. Army Corps of Engineers on standby for assistance. Medical and mortuary teams were also sent by the

U.S. Department of Health and Human Services The United States Department of Health and Human Services (HHS) is a cabinet-level executive branch department of the U.S. federal government created to protect the health of all Americans and providing essential human services. Its motto is " ...

. By May 6, donation centers and phone banks were being established to create funds for victims of the tornadoes. Within the first few days of the disaster declaration, relief funds were sent to families requesting aid. Roughly $180,000 had been approved by FEMA for disaster housing assistance by May 9. Debris removal began on May 12 as seven cleanup teams were sent to the region with more teams expected to join over the following days. That day, FEMA also granted seven Oklahoma counties (

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

, Craig, Grady, Lincoln, Logan, Noble and Oklahoma) eligibility for federal financial assistance. Roughly $1.6 million in disaster funds had been approved for housing and businesses loans by May 13, increasing to more than $5.9 million over the following five days. Applications for federal aid continued through June, with state aid approvals reaching $54 million on June 3. According to FEMA, more than 9,500 Oklahoma residents applied for federal aid during the allocated period in the wake of the tornadoes, including 3,800 in Oklahoma County and 3,757 in Cleveland County. Disaster recovery aid for the tornadoes totaled to roughly $67.8 million by July 2.

Concerns with using overpasses as storm shelters

From a meteorological and safety standpoint, the tornado called into question the use of highway overpasses as shelters from tornadoes. Prior to the events on May 3, 1999, videos of people taking shelter in overpasses during tornadoes in the past (such as an infamous video from the April 26, 1991 tornado outbreak taken by a news crew from Wichita NBC affiliate

KSNW KSNW (channel 3) is a television station in Wichita, Kansas, United States, affiliated with NBC and Telemundo. The station is owned by Nexstar Media Group, and maintains studios on North Main Street in northwest Wichita (near downtown); its tran ...

) created public misunderstanding and complacency that overpasses provided adequate shelter from tornadoes. Although meteorologists had questioned the safety of these structures for nearly 20 years, there had been no evidence supporting incidents involving loss of life. Three overpasses were directly struck by tornadoes during the May 3 outbreak, resulting in fatalities at each location. Two occurred as a result of the Bridge Creek–Moore F5, while the third occurred in rural Payne County, which was struck by an F2 tornado. According to a study by the National Oceanic and Atmospheric Administration, seeking shelter in an overpass "is to become a stationary target for flying debris"; the wind channeling effect that occurs within these structures along with an increase in wind speeds above ground level, changing of wind direction when the tornado vortex passes, and the fact most overpasses do not have girders for people to take shelter between also provide little to no protection.

References

External links

May 3, 1999 Oklahoma Tornado Special Report - The OklahomanGreat Plains Outbreak of 1999
Tornado History Project
The Great Plains Tornado Outbreak of May 3-4, 1999
(National Weather Service, Norman, Oklahoma)
The 3 May 1999 Oklahoma Tornadoes
(David Schultz, CIMMS)
Google Maps' location of Stroud, Oklahoma, with the bulldozed lot of the former Tanger Outlet Mall in the upper left of the screen, just north of Interstate 44
Special video section from

KOCO-TV KOCO-TV (channel 5) is a television station in Oklahoma City, Oklahoma, United States, affiliated with ABC and owned by Hearst Television. Its studios and transmitter are located on East Britton Road (Historic Route 66)—between North Kelley a ...

Moore, Oklahoma Tornado Photos, May 1999
Aerial Photos of Moore Oklahoma taken three days after the May 3, 1999, tornado * {{DEFAULTSORT:Oklahoma F5 tornadoes Tornadoes of 1999 Tornadoes in Kansas Tornadoes in Oklahoma Tornadoes in Texas Natural disasters in Oklahoma Tornadoes in Tennessee Tornado outbreaks 1999 in Tennessee 1999 in Texas 1999 natural disasters in the United States Articles needing additional references from March 2008 May 1999 events in the United States